Post by pxguru on May 24, 2012 4:44:45 GMT 1

I have always wondered what could be done to make a 200 quicker without spending any money. Over the past few months I have been doing some wild experiments with a selection of tungsten carbide bits in my Dremel on spare standard 200 barrel and my otherwise standard PX200disc. So far the results are amazing As it was getting a bit hot and smelly I did have to concede and take off the standard exhaust (now Sterling Performance) but just so you get the idea my standard P200 will now do just over 65mph in third, off the clock just past the H (of mph) in top and is running on a 155 (approx) main jet (home made from a 140). I think the previous long term reliability is now questionable but it goes really well and I am shocked. Would love to race it against a bolt on Malossi sometime If anyone else out there has ever had a fiddle with standard barrel tuning or wishes to risk it all, buy a Dremel and share my numbers you are more than welcome...

Post by sbwnik on May 24, 2012 13:30:19 GMT 1

The best I've come across remains Harry Barlow's kit. Shorten the barrel and make a spacer to raise it back to the right length, this substantially raises the timing and increases power and top end. I raced one on mine, and was left for dead.

Wonderful work.

And a bolted on Malossi would get murdered by anything half serious. A ported Malossi would eat you alive... No middle ground from the ones I've ridden.

SBW Nik - cynical about scooters since 1982, but still refusing to give them up as he hopes one day one of them will prove him wrong.

P200 Day-to-day and Rally bike 'One Careful Owner'
Cosa 200

About to start work on building that rarest of beasts, a Cosa chop. It's taken long enough to get this far, the P207 chop will have to wait a bit longer...

Post by pxguru on May 28, 2012 8:26:58 GMT 1

Thx but this is way beyond just jacking the barrel up. It's entirely re designed port timing with four extra ports of my own and more..... With all the ports there is now over double the transfer area of a standard. I have always fitted kits and just discarded the poor old lump of cast iron without a care. I decided it was high time to give tuning one a proper go before I’m really too old

I set out to make a totally standard P200 go off the clock on the flat with only modified original parts. It’s taken a while but the results are beyond my expectations and thought others should know that it is actually possible. There must be someone who has done the same before me....

As I have achieved this folly (except the exhaust) and before it all ends in tears and the piston breaks up, I’m going to re bore this barrel with one of those 68mm thin ring pistons and grind out 500 more rpm (70 in third would be cool)! Oh, and put a PHBH30 on it as a 155 main jet in a SI24/24E is just plain ridiculous.

A fully sorted Malossi would certainly win but bear in mind this standard barrel is revving to 8000 rpm, goes off the clock between roundabouts and does pull a std 4 th gear up hill. Sounds unbelievable....it still amazes me

Post by jamieallen3166 on May 28, 2012 16:48:57 GMT 1

Guys, once again can't thank you enough for invaluable input. I now have the high load SEB. The cylinder head is being reprofiled. Flywheel seal renewed and bonded in (now no leak). PHBH almost ready for fitting too. Not sure if I will put the PM pipe back on or spend some pennies on a Sito Plus. Once done, results will be posted. Jamie

Post by pxguru on May 30, 2012 4:19:09 GMT 1

jamieallen3166 you're welcome. Put the PM pipe back on! When you fit the new head check the squish clearance is no more than 1.2mm (The fuel compressed in the squish band area at detonation is just wasted as it does not provide any additional power).

Post by pxguru on May 30, 2012 6:18:45 GMT 1

Sbwnik - cheeky! It is just like everyone has ever said, they need too much work and it’s far easier just to buy a kit (and port that!). This version is ott for the piston and will blow up if I carry on but as a thin ring version it will do rallies. There might be something we can do. What’s your current set up? And what kind of riding do you want it for?

Post by sbwnik on May 30, 2012 10:04:12 GMT 1

I wasn't serious, I can see the amount of work that's gone into it and was just wondering if I could get you to swear at me though!

It'd be impractical for me, my P2 is a daily ride - work, shopping, leisure, rallies etc - so I need the standard set up and the reliability that goes with it. It'd be interesting on my Cosa though, but as that's off the road for a while, it's not an issue.

PM though..

SBW Nik - cynical about scooters since 1982, but still refusing to give them up as he hopes one day one of them will prove him wrong.

P200 Day-to-day and Rally bike 'One Careful Owner'
Cosa 200

About to start work on building that rarest of beasts, a Cosa chop. It's taken long enough to get this far, the P207 chop will have to wait a bit longer...

Post by paulesc on Oct 18, 2012 19:13:08 GMT 1

I really like it when people do there own thing. Do u have anymore pics and info you can share. I would like to do this, but not quite so extreme :0)I put an rd 250 reed valve and carb on my last p200. Nice little cheap mod.

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